2.5 16v Timing Chain Nightmare! - Page 4 - PeachParts Mercedes-Benz Forum

Tinker · #46 08-20-2004, 05:10 PM

There is an additional idle switch on the throttle body itself. Three wires. I don't know if that would effect idle. I ran with mine disconnected for a while with no real noteable difference.

How is the vacuum guage reading at idle? Is it pulling the same at idle as it did prior to the repair? Look for a vacuum leak?

The EHA is the black box on the side of the fuel distributor. Ideally, if the mixture is adjusted correctly, one should be able to unplug it at idle with no change in idle speed.

Tinker

Uk Merc Man · #47 08-22-2004, 04:53 PM

right, following on....

as mentioned in my previous post the throttle microswitch has been replaced.

i got the car up to temp and unplugged EHA, no change.

at idle, when rpm is going up and down, vacuum gauge on dash is all over the place, it used to be still.

Next???

thanks

Uk Merc Man · #48 08-23-2004, 04:34 AM

Quote:

Originally Posted by Uk Merc Man

right, following on....

as mentioned in my previous post the throttle microswitch has been replaced.

i got the car up to temp and unplugged EHA, no change.

at idle, when rpm is going up and down, vacuum gauge on dash is all over the place, it used to be still.

Next???

thanks

anyone......

Chris Martens · #49 08-23-2004, 05:42 AM

Steve,

Quote:

as mentioned in my previous post the throttle microswitch has been replaced.

That's the wrong one, there is another idle switch inside the throttle body itself. Three wires as mentioned before, a plug mounted on the intake manifold where you can check the middle pin against the outer ones for continuity.

In idle condition (engine off) there has to be continuity between the middle pin and one outer pin, in full throttle between the middle pin and the other pin.

This switch does influence the idle quality!

Quote:

i got the car up to temp and unplugged EHA, no change.

No change means revs are still changing?
That sounds like a vacuum problem somewhere.

If anything else is fine and the idle switch is broken, unplugging the EHA gives a steady idle at slightly higher revs (1100/min for the 16V).

Quote:

Next???

Check the idle switch.
Check for vacuum leaks. There are some lines that could be cracked or plugged wrong somehow...

I really love this remote surgery

bis denn,
Christian

1989 300TE
1984 2.3-16

Uk Merc Man · #50 08-26-2004, 07:06 AM

update

went to see a mate in the know...

reset my co2 mixture, was off the scale (high) when we started, now at 0.9% - car still doesnt idle but running it off idle through the revs its loads better.

Unplugging the EHA made no difference.

If left the idle does eventually stop surging and settles down to 1000rpm but still rough.

Will be looking for idle faults and bad electrical faults this weekend

any other pointers? - check my thread re tacho/idle connections?

Thanks